Seedbed characteristics ·要紧实,以便种子和根能够接触到土壤颗粒而吸收养分 must be firm to allow seed and root to come in contact with soil particles to absorb moisture ·要有足够的空隙以利于通气、扎根和水分运动 must be porous to allow air to move, root development, water movement If soil is too loose, rain will wash away young plants Air and water conduct heat more rapidly than soil, looser soils warm up sooner; Plant residue on surface insulates, warms up slower, also provides buffer against windSeedbed Characteristics • 要紧实，以便种子和根能够接触到土壤颗粒而吸收养分 must be firm to allow seed and root to come in contact with soil particles to absorb moisture； • 要有足够的空隙以利于通气、扎根和水分运动 must be porous to allow air to move, root development, water movement. • If soil is too loose, rain will wash away young plants； • Air and water conduct heat more rapidly than soil, looser soils warm up sooner； • Plant residue on surface insulates, warms up slower, also provides buffer against wind